Press the button in the lower left hand corner that looks like your blue target and the alignment will pop up

A2:

On the menu where you choose between score attack, multiplayer, and practice , there is a menu on the bottem left of the screen. choose it to make the cross hairs closer to where you are really pointing.

Shoot the circle on the hands, once both hands are gone and the dragon falls, there is a circle on top his head that you need to shoot at as well. It also helps to shoot at the "creatures" that he spits out, it seems like the more you shoot the less time it takes to beat the dragon. It has always taken several times of getting the dragon to fall before I've beaten him.